iommu/arm-smmu: prefer stage-1 mappings where we have a choice

For an SMMU that supports both Stage-1 and Stage-2 mappings (but not
nested translation), then we should prefer stage-1 mappings as we
otherwise rely on the memory attributes of the incoming transactions
for IOMMU_CACHE mappings.

Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 2961b8c..7638b57 100644 (file)
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -876,12 +876,12 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
                 */
                cfg->cbar = CBAR_TYPE_S1_TRANS_S2_BYPASS;
                start = smmu->num_s2_context_banks;
-       } else if (smmu->features & ARM_SMMU_FEAT_TRANS_S2) {
-               cfg->cbar = CBAR_TYPE_S2_TRANS;
-               start = 0;
-       } else {
+       } else if (smmu->features & ARM_SMMU_FEAT_TRANS_S1) {
                cfg->cbar = CBAR_TYPE_S1_TRANS_S2_BYPASS;
                start = smmu->num_s2_context_banks;
+       } else {
+               cfg->cbar = CBAR_TYPE_S2_TRANS;
+               start = 0;
        }
 
        ret = __arm_smmu_alloc_bitmap(smmu->context_map, start,